Conventionally, in the manufacture of semiconductor devices, micro-processing by lithography using a photoresist has been carried out. The micro-processing is a processing method comprising forming a thin coating of a photoresist on a semiconductor substrate such as a silicon wafer or the like, irradiating actinic rays such as ultraviolet rays through a mask pattern on which a pattern for a semiconductor device is depicted, developing it to obtain a photoresist pattern, and etching the substrate using the photoresist pattern as a protective coating, thereby forming fine unevenness corresponding to the pattern on the surface of the substrate. In recent progress in high integration of semiconductor devices, there has been a tendency that shorter wavelength actinic rays are being used, i.e., ArF excimer laser beam (193 nm) has been taking the place of KrF excimer laser beam (248 nm). Along with this change, influences of reflection actinic rays from a substrate have become serious problems. Accordingly, it has been widely studied to provide an anti-reflective coating between the photoresist and the substrate (bottom anti-reflective coating) in order to resolve the problem. As the anti-reflective coating, from a viewpoint of easy of use or the like, many considerations have been done on organic anti-reflective coatings composed of polymers having light absorbing group, etc. For example, the organic anti-reflective coatings include an acrylic resin type anti-reflective coating having hydroxy group being crosslinking reaction group and a light absorbing group in the same molecule, or a novolak resin type anti-reflective coating having hydroxy group being crosslinking reaction group and a light absorbing group in the same molecule. The properties desired for such an anti-reflective coating include high absorbance to light and radioactive rays, no intermixing with the photoresist (being insoluble in photoresist solvents), no diffusion of low molecular substances from the anti-reflective coating into the topcoat photoresist upon baking under heating, and a higher dry etching rate than the photoresist, etc.
In recent years, in order to solve interconnection delay that has become clear with miniaturization in pattern rule of semiconductor devices, it has been also considered to use copper as interconnect material, and to apply Dual Damascene process as interconnect forming method on the semiconductor substrate. And, in Dual Damascene process, via holes are formed and an anti-reflective coating is formed on a substrate having a high aspect ratio. Therefore, the anti-reflective coating for use in this process is required to have filling property by which holes can be filled without gap, flattening property by which a flat coating can be formed on the surface of substrate, and the like. However, it is difficult to apply organic material for anti-reflective coating on a substrate having a high aspect ratio, and in recent years, material with particular emphasis on filling property or flattening property has been developed (see, for example Patent Documents 1 and 2).
In addition, in the production of devices such as semiconductor devices, in order to reduce poisoning effect of a photoresist layer induced by a dielectric layer, there is disclosed a method in which a barrier layer formed from a composition containing a crosslinkable polymer and the like is provided between the dielectric layer and the photoresist layer (see, for example Patent Document 3). Further, in recent years, as an underlayer coating between a semiconductor substrate and a photoresist, a coating known as a hardmask that contains a metal element such as silicon or titanium, etc. has been used (see, for example Patent Documents 4, 5, 6 and 7). In this case, as the photoresist and the hardmask are largely different from each other in the constituent components, rates at which the components are removed by dry etching depend largely on the kind of gas used for dry etching. An appropriate selection of the kind of gas makes possible to remove the hardmask by dry etching without significant decrease in film thickness of the photoresist. Therefore, in case where a photoresist and a hardmask are used, it is assumed that a film thickness sufficient for a protective coating (composed of a photoresist and a hardmask) for semiconductor substrate processing can be ensured even when the photoresist is a thin coating.
As mentioned above, in the recent manufacture of semiconductor devices, in order to exert several effects in addition to anti-reflective effect, it is getting larger that an underlayer coating is provided between a semiconductor substrate and a photoresist. Although the compositions for the underlayer coatings have been considered, it is desired to develop novel materials for underlayer coatings from the diversity of characteristics required therefor and the like.
On the other hand, a composition and a method for forming a pattern in which a compound having a bond between one silicon and another silicon (silicons) is used are known (see, for example Patent Documents 8, 9, 10, 11 and 12).
An anti-reflective layer forming composition comprising a polymer containing a novolak-like silane is disclosed. The polymer contains a novolak group at the main chain and a cluster-like silane at the side chain. The composition can comprise an acid generator and a crosslinking compound (see, for example Patent Document 13).    Patent Document 1: JP-A 2002-47430    Patent Document 2: WO 02/05035 pamphlet    Patent Document 3: JP-A 2002-128847    Patent Document 4: JP-A 11-258813    Patent Document 5: JP-A 2001-53068    Patent Document 6: JP-A 2005-55893    Patent Document 7: JP-A 2005-15779    Patent Document 8: JP-A 10-209134    Patent Document 9: JP-A 2001-55512    Patent Document 10: JP-A 10-268526    Patent Document 11: JP-A 2005-48152    Patent Document 12: JP-A 2002-107938    Patent Document 13: JP-A 2005-115380